Pops an element from the queue and returns a pointer to that element. The value of the element must then be copied from the location pointed to before calling push() or pop() the next time.
pointer to the element popped from the queue or null if the queue is empty.
See Implementation
Pops an element from the queue and returns a pointer to that element. The value of the element must then be copied from the location pointed to before calling push() or pop() the next time.